Failure to induce nitric oxide production by human monocyte-derived macrophages. Manipulation of biochemical pathways.
Production of nitrix oxide (NO-) by human macrophages is controversial. In the present study, the ability of human monocyte-derived macrophages (M phi) to produce NO- in response to M phi modulators was tested. M phi cultured for up to nine days and stimulated for 48 with different concentrations of LPS and/or IFN-gamma failed to produce significant amounts of NO2- compared to unstimulated cultures. Inhibition of the cyclo-oxygenase pathway with indomethacin did not increase NO2- production by LPS stimulated M phi. Since human M phi lack biopterin, needed for NO- synthesis by murine M phi, human M phi stimulated with LPS plus IFN-gamma were additionally cultured in the presence of neopterin or biopterin. These treatments did not induce NO2- production. Furthermore, simultaneous treatment with indomethacin and neopterin or biopterin also failed to induce NO2- production. However, human M phi, stimulated with IFN-gamma and LPs, produced TNF-alpha suggesting that the lack of increment in NO2- production was not due to an absence of response of M phi to the stimuli used. As an indirect approach to explore the NO- production, human M phi were infected with virulent Mycobacterium tuberculosis H37Rv and simultaneously treated with the competitive inhibitor NGmonomethyl-L-arginine (NGMMA). Mycobacterial intracellular replication was measured by 3H-uracil incorporation. NGMMA did not have any effect on mycobacterial replication. These results further suggest that human M phi do not produce NO- at least by the inducible pathway.
Arias
M
M
Laboratorio Central de Investigaciones, Facultad de Medicina, Universidad de Antioquía, Medellín, Colombia.
Zabaleta
J
J
Rodríguez
J I
JI
Rojas
M
M
París
S C
SC
García
L F
LF
D001708:Biopterins / Q000494:pharmacology; D002478:Cells, Cultured / Q000187:drug effects; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology; D009000:Monocytes / Q000166:cytology*; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000254:growth & development; D019798:Neopterin / Q000494:pharmacology; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology
D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D001708:Biopterins; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D019798:Neopterin; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D007213:Indomethacin